Two polarizers are oriented with their principal planes making an angle of $60^{\circ}$ with each other. The percentage of incident unpolarized light which passes through the system is: (in $\%$)

$n$ polarizing sheets are arranged such that each makes an angle $45^{\circ}$ with the preceding sheet. An unpolarized light of intensity $I$ is incident on this arrangement. The output intensity is found to be $\frac{I}{64}$. The value of $n$ will be:

Two polaroids have their polarizing directions parallel so that the intensity of the transmitted light is maximum. The angle through which either polaroid must be turned so that the intensity of the transmitted light is dropped to one-half of the previous transmitted intensity is $.....^\circ$.

$A$ polariser is used to

Consider the following statements $A$ and $B$. Identify the correct choice in the given answers.
$A$. The refractive index of the extra-ordinary ray depends on the angle of incidence in double refraction.
$B$. The vibrations of light waves acquire one-sidedness for both ordinary and extraordinary rays in double refraction.

$A$ beam of plane polarized light falls normally on a polarizer of cross-sectional area $3 \times 10^{-4} \, m^2$. The flux of energy of the incident ray is $10^{-3} \, W$. The polarizer rotates with an angular frequency of $31.4 \, rad/s$. The energy of light passing through the polarizer per revolution is: